In treatment of blood-related diseases such as leukemia, and in surgical treatment, it is very important to stably amplify and supply blood cells in an amount necessary for the treatment. For this purpose, a number of medical workers have devised various means for securing the blood cells. For example, collection of blood from donors and induction of differentiation from cord blood or bone marrow cells have been conventionally carried out.
In recent years, attempts are being made to efficiently amplify hematopoietic stem cells or hematopoietic progenitor cells, which can be used as a source for production of blood cells, using cells having pluripotency such as embryonic stem cells (ES cells) or induced pluripotent stem (iPS) cells obtained by introduction of undifferentiated-cell-specific genes into somatic cells (e.g., Patent Documents 1 and 2).
Examples of methods for inducing differentiation of ES cells or iPS cells into hematopoietic stem cells and/or hematopoietic progenitor cells that have been reported so far include a method by formation of embryoid bodies and addition of cytokine (Non-patent Document 1), a method by co-culture with stromal cells derived from a different species (Non-patent Document 2), and a method using a serum-free medium (Patent Document 3).
However, further improvement is necessary for enabling their application to medical treatment, and establishment of more efficient methods for differentiation induction, identification of novel differentiation-inducing factors, and methods for selecting productive cells in a stage before carrying out differentiation induction treatment, are demanded.